The paper analysed some aspects of changes in the biological structures of the population in 230 settlements of West Morava Valley, from the position of the type of settlement and the hypsometric zone to which they belong. Bearing in mind that there are significant height differences in the relief of West Morava Valley (144-1,321 m above sea level), its breakdown caused the regional differentiation of settlements according to the size and structures of the population living in them. The statistical analysis was performed in two-period sections (1971 and 2011). The reason for this is that the 1970s were the most dynamic socio-economic transformation of the studied region, caused by the impact of industrialization and urbanization. The results obtained during the research show that the aging of the population in West Morava Valley has reached such a level that it represents a first-class problem. In the analysed forty-year period, the participation of the old population (60 and over) doubled (from 12.8% to 25.2%), while the aging index increased even three times (from 0.42 to 1.27). The population of West Morava Valley is in the stage of the deepest demographic age, with the difference that rural settlements at higher altitudes age much faster. The differences in the gender structure of the population between the urban and rural settlements of the region are not so drastically expressed, but in both categories the dominance of the female contingent is evident.